Hi SnowLeopard25,
With your concerns over tax deduction and calculation, I would suggest checking with an accounting professional. My understanding is you'd still record expenses as they are and record another income once you got your tax return from the ATO. I have shared a link to our Fine A ProAdvisor page with you before in one of your previous posts, but here it is again:
Find an accounting advisor near you
You may also discuss business vs. private use expense with your accountant as well.
Hope this helps and please let us know if you have any questions.
